Connective and Nervous Tissue: Lab 4

• Lab 4 covers connective and nervous tissue.

Functions of Connective Tissue

• Connective tissue encloses and separates organs, muscles, nerves, and blood vessels.
• Connective tissue connects structures such as tendons (muscle to bone), ligaments (bone to bone), and fascia (muscle to muscle).
• Connective tissues support movement with bones (rigid support) and cartilage (flexible support).
• Adipose tissue stores fat.
• Bone tissue stores calcium and phosphate.
• Adipose tissue is used for cushioning and insulation.
• Blood transports substances.
• White blood cells (WBC) protect as part of the immune system.

Composition of Connective Tissue

• Connective tissue contains cells and extracellular matrix.
• "-blast" cells create matrix.
• "-cytes" cells maintain matrix.
• "-clasts" cells break down matrix.
• Extracellular matrix consists of protein fibers (produced by fibroblasts), ground substance, inorganic components, and fluids
• Protein fibers include collagen, elastin, and reticulin.

Loose Connective Tissue

• Loose connective tissue includes areolar or subcutaneous connective tissue
• All three fiber types are present
• Loose connective tissue is located under the skin.
• Loose connective tissue is a loose "packing" material found between muscle layers and around nerves and blood vessels.
• Fibroblasts make the protein fibers.
• Mast cells release histamine to induce inflammation in response to injury.

Dense Regular Connective Tissue

• Dense regular collagen has collagen arranged parallel, making it very strong.
• Tendons and ligaments are examples of dense regular collagen.
• Dense regular elastic has collagen and elastin arranged parallel, making it strong and elastic.
• Vocal cords and the nuchal ligament are examples of dense regular elastic.

Dense Irregular Connective Tissue

• Dense irregular collagen has collagen in all directions and is strong.
• Dense irregular elastic has collagen and elastin in all directions, making it strong and elastic.
• Walls of arteries are an example of dense irregular elastic.

Adipose Tissue

• Adipocytes store lipid droplets.
• Adipose tissue has very little matrix and collagen, and it is located under the skin.
• The primary function of adipose tissue is energy storage.
• The secondary function of adipose tissue is insulation and cushioning.

Reticular Connective Tissue

• Reticular connective tissue has a delicate network of reticular fibers.
• It forms the framework for lymph tissue found in lymph nodes, the spleen, and tonsils.

Cartilage

• Cartilage provides strong support with flexibility.
• Cartilage reduces friction and wear and tear, and provides shock absorption.
• Cartilage does not have nerve fibers and contains no blood supply (avascular).
• Cartilage consists of a solid matrix and chondrocytes.
• Lacunae are "little lakes," open spaces in the solid matrix where chondrocytes are located.
• Perichondrium has a dense irregular collagen membrane around cartilage.

Types of Cartilage

• Hyaline cartilage contains collagen fibers
• Costal cartilage, articular cartilage, tracheal rings, and nasal septum are examples of hyaline cartilage.
• Fibro-cartilage has lots of collagen, making it very strong where there is great pressure.
• Knee, jaw, vertebrae, and pubic bone are examples of fibro-cartilage.
• Elastic cartilage has collagen and elastin.
• The pinna and epiglottis are examples of elastic cartilage.

Bone Tissue

• Bone tissue provides strong, rigid support and contains collagen with a solid ground substance.
• Osteon is the structural subunit.
• Osteon look like a circle with "tree rings."
• Osteocytes are located in lacunae.
• Hydroxyapatite is crystallized calcium and phosphate.

Blood

• Blood contains cells (Red blood cells, white blood cells and platelets).
• Red blood cells (RBC) transport blood gases.
• White blood cells (WBC) provide immune functions.
• Platelets are responsible for clotting.
• Blood has a liquid matrix called plasma, which transports dissolved substances.

Nervous Tissue

• Organs of the nervous system include the brain, spinal cord, and nerves.
• Functions detect sensory information; process information; relay commands for responsive actions; and maintainhemostasis.
• Cell types in nervous tissue include neurons and neuroglia.
• Neurons conduct electrical signals and facilitate communication.
• Neuroglia gives neuronal support, nourish, protect and insulate.